Rheology of aqueous polyurethane dispersions: Links between flow and particle interaction

The flow properties of three aqueous polyurethane dispersions are characterized as a function of particle concentration. The particles are highly charged. Using a series of simplified methods pioneered on model suspensions, particle interaction energies capable of describing osmotic pressure, continuous shear, and elastic behavior are developed. Electrostatic forces dominate particle interactions at low volume fractions. At elevated concentrations, short range repulsive interactions dominate flow properties.